The sense of taste is a major form of chemosensory input in the animal kingdom. Taste perception is responsible not only for attraction and repulsion to various food sources, but also for providing important information about the chemical environment. Our long-term goal is to define the components required for orchestrating the response of a taste receptor cell to its cognate ligands, and to help elucidate the logic of taste coding. This grant focuses on the identification of taste signaling molecules. We will: (1) Generate single cell libraries, perform differential screens and use subtraction approaches to identify genes expressed in subsets of taste receptor cells. These studies will use genetically marked cells isolated from mice expressing fluorescent reporters in defined subsets of taste receptor cells. (2) Develop heterologous expression system to (a) assay taste receptor function, and (b) to functionally clone novel receptors and downstream signaling molecules. We will also isolate and characterize "accessory" proteins required for receptor trafficking and maturation. Finally, (3) we will attempt to identify the genes responsible for taste defects in the sac, soa, rua and qui mutant strains.